The present invention relates to a lens holder (lens mount) provided with a lens holding frame which holds a lens of a camera, binoculars or the like having a circular outer diameter so that the optical axis of the lens will lie in a predetermined position.
When mounting a lens to a lens holding frame, it is required to mount the lens so that the optical axis of the lens will lie in a predetermined position. Therefore, not only the accuracy of the parts has been improved, but also various contrivances have been made.
For example, in order to control the slippage of the optical axis due to production error of a part, it has been proposed to force the lens at the outer diameter thereof. However, in this method, stress applied to the lens due to force fit may deform the lens, thereby causing the deterioration of the optical performances.
Moreover, as a widely and generally used method, there is also a method of controlling the slippage of the optical axis by forming three projections on the lens holding frame, holding the lens by an inscribed circle thereof, and reducing manufacturing error of a part as much as possible. Further, by increasing the number of the projections to six, it is also possible to control the variation of the position of the lens. However, when trying to position a circular object at not less than three points, it cannot be expected which projections will position the circular body depending upon the result of the projections, and therefore, it is difficult to improve the accuracy of the parts dimensions.
As described above, various contrivances have been made so that the optical axis of the lens will lie in a predetermined position when mounting the lens to the lens holding frame, however, it has not been attained yet to control the variation of the lens position due to production error of a part by a simple structure.
The present invention has been made in consideration of the above-described problems and has an object of providing a lens holder being capable of controlling the variation of the lens position due to manufacturing error of a part by a simple structure.
According to a first aspect of the present invention, there is provided a lens holder provided with a lens holding frame which holds a lens having a circular outer diameter, comprising:
a first holding member disposed on the inner diameter of the lens holding frame and having a plurality of main-receiving surfaces so that an inscribed circle corresponding to the outer shape of the lens will be formed; and
a second holding member disposed on the inner diameter of the lens holding frame and having a plurality of sub-receiving surfaces so that an inscribed circle having a larger diameter than that of the inscribed circle formed by the first holding member will be formed.
According to a second aspect of the present invention, there is provided a lens holder provided with a lens holding frame which holds a lens having a circular outer diameter, comprising:
a plurality of first projections formed at a first radius distance from the central axis of the lens holding frame in the circumferential direction in order to bring the lens into collision with them and to position the lens; and
a plurality of second projections formed at a second radius distance larger than the first radius distance from the central axis of the lens holding frame in the circumferential direction in order to bring the lens into collision with them and to position the lens, wherein
the first radius distance of the first projections is slightly larger than the dimension of the outer diameter of the lens, and therefore, the lens can be fitted and held, and
when the lens moves in the vertical direction to the optical axis due to fitting play between it and the first projections, the amount of movement of the lens is controlled within a predetermined amount by the second projections.
According to a third aspect of the present invention, there is provided a lens holder provided with a cylindrical member for holding a lens having a circular outer diameter, comprising:
at least not less than three first projections protruding towards the central axis of the cylindrical member and formed on the inner surface of the cylindrical member for holding the lens by the tips thereof colliding with the outer circumference edge of the lens, the diameter of the circle to which the tips of the first projections are inscribed being slightly larger than the outer diameter of the lens; and
at least not less than three second projections protruding towards the central axis of the cylindrical member and formed on the inner surface of the cylindrical member for holding the lens by the tips thereof colliding with the outer circumference edge of the lens, the diameter of the circle to which the tips of the second projections are inscribed being larger than the diameter of the circle to which the tips of the first projections are inscribed, wherein
when the lens moves in the vertical direction to the optical axis due to fitting play between it and the first projections, the amount of movement of the lens is controlled by the outer circumference edge of the lens colliding with the second projections.
According to a fourth aspect of the present invention, there is provided a lens holder provided with a lens holding frame which holds a lens having a circular outer diameter, comprising:
a plurality of first hold members formed at a position with which the outer circumference of the lens can collide along the circumferential direction of the lens holding frame in order to control the optical axis of the lens in the vicinity of an ideal position to the lens holding frame, wherein by at least a part of the plurality of first hold members colliding with the outer circumference of the lens, the position of the lens can be controlled so that the amount of the slippage of the position of the lens to the ideal position will lie between a first value and a second value; and
a plurality of second hold members formed at a position with which the outer circumference of the lens can collide along the circumferential direction of the lens holding frame, wherein by at least a part of the plurality of second hold members colliding with the outer circumference of the lens, the position of the lens is controlled so that the amount of the slippage of the position of the lens to the ideal position will be smaller than the second value.
According to a fifth aspect of the present invention, there is provided a lens holder provided with a cylindrical member for folding a lens having a circular outer diameter, comprising:
at least not less than three first projections protruding towards the central axis of the cylindrical member and formed on the inner surface of the cylindrical member for holding the lens by the tips thereof colliding with the outer circumference edge of the lens, the diameter of the circle to which the tips of the first projections are inscribed being slightly larger than the outer diameter of the lens; and
at least not less than three second projections protruding towards the central axis of the cylindrical member and formed on the inner surface of the cylindrical member for holding the lens by the tips thereof colliding with the outer circumference edge of the lens, the diameter of the circle to which the tips of the second projections are inscribed being larger than the diameter of the circle to which the tips of the first projections are inscribed, wherein
when the lens moves in the vertical direction to the optical axis due to fitting play between it and the first projections, the amount of movement of the lens is controlled by the outer circumference edge of the lens colliding with the second projections.
According to a sixth aspect of the present invention, there is provided a lens holder for holding a lens having one optical axis comprising:
a lens holding frame having a virtual axis with which the optical axis of the lens is to be coincided; and
a holding member including:
a first holding member for controlling so that the distance between the optical axis and the virtual axis will be smaller than a first distance when the lens is fitted in the lens holding frame; and
a second holding member for controlling so that the distance between the optical axis and the virtual axis will be smaller than a second distance when the lens is fitted in the lens holding frame.
According to a seventh aspect of the present invention, there is provided a lens holder provided with a lens holding frame having an opening for holding a lens, comprising:
three first protruding parts protruding into the opening for holding the outer circumference of the lens; and
second protruding part protruding into the opening so as to be able to collide with the outer circumference of the lens and formed so as not to enter an inscribed circle formed by the three first protruding parts.
According to an eighth aspect of the present invention, there is provided a lens holder provided with a lens holding member for holding a lens, comprising:
a first position control member provided in the lens holding member and being capable of controlling the movement of the lens; and
a second position control member provided in the lens holding member and being capable of controlling the movement of the lens, wherein
the first position control member and the second position control member are set so that the gap between the lens and the second position control member will be larger than the gap between the lens and the first position control member.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.